Alternative Gas Cap

[Stage2Tahoe]

I have had my issues with the EVAP/Fuel tank and I still get a tighten gas cap at around a 1/4 tank. I still have to take the cap off and reinstall but it clears and everything is good. This leads to my question. I have the yellow e85 cap and I honestly will never run e85. Is there an alternative gas cap that can be used to replace it? Mine never tightens the same way twice and I want a cap that tightens and stays secure. I think the pressures in the tank are causing it to loosen which is creating the problem. I have looked at all of the caps that come standard for My 08 tahoe and they all seem to be the same style. Only difference is the 85 being yellow compared to the Gas being Black.

 

[Doubeleive]

I have had my issues with the EVAP/Fuel tank and I still get a tighten gas cap at around a 1/4 tank. I still have to take the cap off and reinstall but it clears and everything is good. This leads to my question. I have the yellow e85 cap and I honestly will never run e85. Is there an alternative gas cap that can be used to replace it? Mine never tightens the same way twice and I want a cap that tightens and stays secure. I think the pressures in the tank are causing it to loosen which is creating the problem. I have looked at all of the caps that come standard for My 08 tahoe and they all seem to be the same style. Only difference is the 85 being yellow compared to the Gas being Black.

Same cap it wwas just colored yellow so people would realize they could use e85

 

[Stage2Tahoe]

So.... Is there a different cap that works better than the factory style? I'm not a fan of the breakaway type cap. Do the newer vehicles have to run that type for the fuel system to function properly?

 

[tom3]

I wonder if you have another problem in the evap.system that is causing an improper pressure situation? Newer vehicles don't have a removable cap, just a spring loaded flap and seal.

 

[buckwild27]

The vent for the evap system could be plugged. As said above, newer vehicles don't have a cap unless it has the flex fuel option on it. Then it has a yellow cap Like you already have.

 

[Stage2Tahoe]

I have gone over the system and I have replaced the purge valve. thinking that was the problem. I have tried a new gas cap and that didn't fix it. I pulled the evap canister and removed the charcoal because I was having an issue when filling up at the gas station. I noticed that I have one line that has a broken clip at the evap canister, but I don't know enough about the newer fuel systems to know what else to look for. there is a seperate pump under the back of the tahoe that is part of the system, but I haven't researched to figure out the function.

 

[Fless]

I'd say try a purge and seal test, and possibly use a smoke machine on it. Also a loose seal anywhere in the system -- like at a vent line connection -- can cause this. Forget about the gas cap for now and use some diagnostic tools on it.